Plate clamp



A. S. BUSK PLATE CLAMP Jam, 1938.

Filed Dec. 18, 1935 2 Sheets-Sheet l R Y O K m W m W5 A 5 r m m N H Y Wm B m :IH Nm i w mm w n w -i! QM A N r E wk Q TFTIAJ Q n m III-In dfi vw I I I l I l l I I l i I ll A. S. BUSK Jan. 11, 1938.

2 Sheets-Sheet Filed Dec. 18, 1935 INVENTOR. 6 How 5 05K ATTORNEY.

Patented Jan. 11, 1938 iJNi'iED STATES FATEN'E GFFIQE PLATE CLAMP Anthony S. Busk, Paterson, N. J., assignor to New Era Manufacturing Company, Paterson, N. J., a corporation of New Jersey Application December 18, 1935, Serial No. 54,997

20 Claims. (01. 101-415.!)

My invention relates generally to plate-cla ps? showing the cylindrical segment withdrawn below for printing-press cylinders where it is desired to the peripheral surface of the cylinder when the have substantially the entire circumference of plate is to be loosened and removed;

the cylinder utilized for impression or platB- Fig. 4 is a detailed end view looking from the 2' supporting purposes as is common in web printright of Fig. 1; ing-presses, and my invention particularly relates Fig. 5 is an enlarged detailed section showing to improved clamping mechanisms for fastening the plate ends held by the clamp with a practifiexible sheets or plates in even and firm contact cally continuous printing surface for the cylinder; with the printing-press cylinder and is especially and adapted for securing the zinc plates Wrapped Fig. 6 is a perspective View of the flexible plate.

about the cylinders in offset printing-presses, Similar numerals refer to similar parts though it may be used to advantage in other types throughout the several figures. of presses. Referring to the drawings and particularly to The objects of my invention are, among other Fig. l, the press cylinder 1 is of the usual hollow things, to provide a simple, novel and efficient construction having the peripheral cylindrical 1 clamp mechanism for such printing plates which side walls 8 with the bearers 9 and H] at either plate-clamps will be convenient to operate and end, the cylinder 1 being mounted'on the axiallywhich will strain and hold the plate wrapped disposed supporting shaft II to which is fastened about the cylinder surface with a uniform and the driving gear 1 2. Integral with the cylinder 2Q. equalized tension so as to prevent any wrinkles I and bearers 9 and m is the irregular shaped 0 or unevenness on the surface of the plate, thereby counter-sunk web l3 (Figs. 2 and 3), which terensuring accurate printing; furthermore to prominates with the cylinder side walls 8 to form the vide a plate-clamp mechanism of such a char transverse edges l4 and I5 coincident with the actor that permits substantially all the continuous peripheral surface of the cylinder 1 with the printing surface of the cylinder to be used, which transverse gap or wide slot lfi within which is 25 object I accomplish by utilizing the cylinder plate fitted the transverse cylindrical segment ll of clamping mechanism as part of the cylinder the same degree of curvature as the side Walls 8 printing surface when the plate has been posiof the cylinder 1, as shown in Figs. 1 and 2. tione d and secured for printing. The cylindrical segment 11 carries lugs l8 at so. A further feature of my invention is the proeither end journalled in the stud-bolts l9 that visidn of an improved plate-clamp embodied are secured in holes 20 drilled in either end of the within the cylindrical contour of the cylinder and cross-shaft 2|, the stud-bolts l9 being journalled having the desired attributes of simplicity, eifiin the bearers 9 and ID as shown in Fig. 1. To ciency and durability, by which the flexible plate the outer ends of the stud-bolts l9 are keyed the 5. may not only be clamped to the cylinder but also brackets 22 to which are pivoted the short rods loosened therefrom, both easily and quickly, with 23 that are adapted to slide in the apertured the likelihood of mutilation of the plates reduced lugs 24 fastened to the bearers 9 and ID as shown to aminimum in that the operations of the clampin Fig. l. Coiled about the rods 23 between the ing devices are conveniently located outside the lugs 24 and the inner base of the rods 23 (Figs.

40.. Zone of the printing plate wrapped about the l and 4) are the two compression springs 25 cylinder. that normally hold the depending brackets 22 in With these and other objects in view, my intheir radial position as shown in Fig. 4. The

vention comprises the construction, combination outer surfaces of the brackets 22 and adjacent and arrangement of the various parts hereinafter ends of the stud-bolts l9 have holes 25 formed described, and then particularly pointed out in therein for the insertion of any suitable pin-bar 5 the appended claims. or bolt 21 (shown in dot and dash lines in Fig. 4)

In the accompanying drawings, Fig. 1 is a plan to rock the brackets 22' in an anti-clockwise direcview of the press cylinder, partly broken away tion as shown by the arrow in Fig. 4 against the to show the structure of the plate-clamp, the tension of the springs 25.

5 right portion of this figure showing a portion of The cylindrical segment I! is so shaped that its the flexible plate wrapped about the cylinder outer surface 28 when the segment is raised to its in clamped position; normal operative position (Fig. 2) snugly fits Fig. 2 is a sectional view on the line 2--2 of within the transverse opening l6 and is a part of the printing surface of the cylinder 1 extending v Fig. 3 is a. sectional view similar to Fig. 2, but from the transverse edge 15. When the segment 55 I1 is lowered by pivoting on the cross-shaft 2| to its Fig. 3 position, it no longer forms a part of the printing surface between the transverse edges I4 and I5 of the cylinder I and no longer is in contact with, nor does it serve as a support for, the flexible plate P shown as wrapped about the cylinder I (Figs. 2 and 3).

Means for raising and lowering this segment I! on its pivoted support on the cross-shaft 2% may be widely varied: In the embodiment illustrated in Figs. 1-4, I have shown a preferred mechanism which effectively accomplishes this purpose. Extending inwardly from the lugs I8 of the segment I! are spaced apart webs in the form of integral short arms 29 (four being shown in dotted lines in Fig. l). Fastened to the outer (and lower) ends of the arms 29 are four rounded flat plates 39, preferably of hardened steel. Opposite and in spaced parallelism with. the plates 38 are rounded flat buttons 3|, also preferably made of hardened steel, that are welded or rigidly secured to the body of the web 53. Extending transversely through the cylinder l and journalled in the bearers 9 and ill is the cylindrical cross shaft 32 arranged between the plates and buttons 3| with fiat cut-out portions 33 formed in the cylindrical surface of the shaft 32 between the oppositely disposed plates 30 and buttons 3i, all as shown in Figs. 1-3. Pinned to the end of the shaft 32 adjacent the bearer I?! is the circular boss 34 having the hole 35 cut in its outer surface for the insertion of a pin-bar 36 (shown in dot and dash lines in Fig. 4) in order to shift the boss 34 and so rock the shaft 32 in either direction.

The boss 34 has formed therein the elongated concentric slot 31 through which projects the threaded bolt 38 having the squared head 39 by which the position of the cross-shaft 33 and boss 34 may be rigidly secured in any predetermined position within the slot 3?. Fig. 2 shows the plates 30 and buttons 3| braced apart to hold the segment I! in its raised position coincident with the sidewalls 8 of the cylinder I, while Fig. 3 showsthe cut-out portions 33 of the shaft 32 in surfaceto-surface contact with the fiat plates 3|] to permit the segment IT to swing inwardly on the shaft 2| below the cylinder surface, and so out of contact with the plate P.

The plate-clamping mechanism proper comprises the cross-shaft 2| that rocks in either direction (Fig. l), the under part 45) of the crossshaft bearing on a flat elongated plate 4|, preferably of hardened steel. which is secured transversely across the cylinder below the transverse edge I4. As shown in Figs. 2 and 3 the shaft 2| has a limited rocking movement with its under part 48 bearing on the plate 4|. Projecting upwardly from, and integral with, the shaft 2| is the clamping plate 42 with its upper end having a recessed portion 43 (Fig. 5) and its top or exposed surface lying in parallelism with the transverse edge |4 in the small opening between the edge I4 and the adjacent edge 44 of the segment I! and coincident with the cylindrical surfaces of the cylinder i and segment II.

When the stud-bolts I9 are rocked by the brackets 22 against the tension of the springs 25, the clamping plate 42 on the shaft 2i has a limited' rocking movement between the transverse edge I4 and the segment IT with the under part 4|! bearing on the plate 4| (Fig. 1).

The plate P is shown in Fig. 6 and is the customary flexible plate of zinc for use in offset printing. Each end of the plate P has rightangled bent-over ends 45 and 46 to a depth of about A, inch. The distance between the bent edges 45 and 46 of the plate P is equal to the circumference of the cylinder s less twice the thickness of the plate P as shown in Figs. 2, 3, and 5.

In operation in fastening the plate P to the cylinder I, the presman inserts the pin-bar 35 in the hole 35 and moves the bar 35 in the direction of the arrow in Fig. 4, which movement rocks the shaft 32 so that the cut-out portions 33 come into surface contact with flat plates 30 so as to permit the segment I? to drop or swing inwardly on the stud-bolts I9 as shown in Fig. 3 with outer surface of the segment I! below or inside the periphery of the cylinder I itself. The stud-bolts I9 journalled in the cross-shaft 2| are then moved by the pin-bar 2! to the left in Fig.

4 which swings the clamping plate 42 to the right in Fig. 3 against the tension of the springs 25. Then the front bent-over end 45 of the plate P is placed transversely between the cylinder edge I4 and the clamping plate 42 which is then allowed to pinch the plate end 45 against the transverse edge I4 by the force of the released springs 25. The cylinder I is then rotated one revolution so as to wrap the plate P about the cylinder. Thereafter the clamping plate 42 is opened again by moving same in a clockwise direction in Fig. 3, and the rear end 46 of the plate P is fitted over the top of the clampingv plate 42 (Figs. 3 and 5) and adjacent the front end 45 so that the clamping plate 42 holds both plate ends 45 and 45 in surface-to-surface contact with the transverse edge 44. Then by means of the pin bar 36, the'pressman turns the shaft 32 until the full diameter of the shaft is wedged between the plates 30 and buttons 3| thereby raising the segment I! to its Fig. 2 position with the periphery of this segment forming a part of the true periphery of the cylinder I (Fig. 2).

This raising of the segment I! to the position shown in Figs. 2 and 5 strains and holds tight the plate P wrapped about the cylinder I to bring the plate in accurate position for printing. The pressman then locks the segment I! in its normal position to hold the plate by screwing home the threaded bolt 38 by means of a wrench acting on the squared head 39 to prevent any rotary movement of the shaft 32.

To loosen and remove the plate P from the cylinder 1, the operations are substantially the same but in a reverse order, and need not be described in detail except that should the segment I! fail to drop from its Fig. 2 position when the shaft 32 is rotated to its Fig. 3 position, a slight movement of the clamping plate 42 in a clockwise position in Fig. 3 will lower the seg ment I! and so release the tension on the plate P so that its bent-over ends 45 and 45 may be sequentially detached from their mutual surface contact in the narrow opening between the transverse edge I4 and adjacent recessed portion 43 of the clamping plate 42. (Figs. 2, 3, and 5.)

According to my invention I have employed the segment I! together with the top surface of the clamping plate 42 as part of the cylinder printing surface as well as an element in the clamping mechanism so as to permit the use for printing of practically the entire circumferential printing surface of the cylinder I as clearly shown in Fig, 5.

My invention is not to be restricted to the precise details of construction shown, since various changes and modifications may be made therein without departing from the scope of the invention or sacrificingthe advantages derived from: its use.

I claim as my invention:

1. In a printing cylinder having a gap and having a flexible platewrapped about the cylinder with both bent-over ends of the plate arranged in mutual parallelism within the gap adjacent one of the edges of the gap, a clamping member, and means for yieldingly moving said member angularly with respect to the cylinder to grip both bent-over ends of the plate against said edge.

2. A printing cylinder having a gap, a clamping member within the gap to grip both ends of a flexible plate wrapped about the cylinder, andspring-pressed means for holding said member against the plate ends to press the latter against one of the edges of the gap.

3. A printing cylinder having a gap, a clamping member within the gap to grip both ends of a flexible plate wrapped about the cylinder, springpressed means for holding said member against the plate ends to press the latter against one of the edges of the gap, and a plate-supporting segment movable outwardly within the gap for tensioning the plate on the cylinder.

4. A printing cylinder having a gap, a clamping member within the gap to grip both ends of a flexible plate wrapped about the cylinder, springpressed means for holding said member against the plate ends to press the latter against one of the edges of the gap, and a plate-supporting segment movable outwardly within the gap to bring the segment surface coincident with the cylinder surface for tensioning the plate on the cylinder.

5. A printing cylinder having a gap, a clamping member within the gap to grip both ends of a flexible plate wrapped about the cylinder, springpressed means for holding said member against the plate ends to press the latter against one of the edges of the gap, and. a plate-supporting segment adjacent said clamping member and movable outwardly within the gap for tensioning the plate on the cylinder, while forcing the clamping member against the plate ends to lock the plate on the cylinder in printing position.

6. A printing cylinder-having a gap, a longitudinally-disposed clamping plate within the gap in parallelism with oneof the edges of the gap, spring-pressed means normally forcing said clamping plate against the bent-over ends of a flexible plate wrapped about the cylinder to grip and hold the ends against said edge, a platesupporting segment pivoted within the gap to form a part of the cylinder surface, and means for raising and lowering said segment without moving the clamping plate to tension and loosen the plate on said cylinder.

7. A printing cylinder having a gap, a longitudinally-disposed clamping plate within the gap in parallelism with one of the edges of the gap, spring-pressed means normally forcing said clamping plate against the bent-over ends of a flexible plate wrapped about the cylinder to grip and hold the ends against said edge, a plate-supporting segment pivoted within the gap to form apart of the cylinder surface, and means for raising said segment coincident with the periphcry of the cylinder to tension and for lowering said segment out of contact with the plate to loosen the latter without moving the clamping in' parallelism with one of the edges of the gap, spring-pressed means normally forcing said clamping plate against the bent-over ends of a flexible plate wrapped about the cylinder to grip and hold the ends against said edge, a platesupporting segment pivoted within the gap to form a part of the cylinder surface, means for raising and lowering said segment without moving the clamping plate to tension and loosen the plate on said cylinder, and means for locking said last means in either position.

9. A plate-clamp for holding a flexible plate having right-angled bent-over ends and wrapped about a printing cylinder having a gap comprising a spring-pressed clamping member to grip and hold the plate ends interposed between the member and one of the edges of the gap, and a platesupporting segment movable within the gap to tension the plate on the cylinder and form a part of the cylinder surface, one edge of the segment bearing on the clamping member opposite to the plate ends to look the plate under tension on the cylinder.

10. A plate-clamp for holding a flexible plate having right-angled bent-over ends and wrapped about a printing cylinder having a gap comprising a spring-pressed clamping member to grip and hold the plate ends interposed between the member and one of the edges of the gap, and a plate-supporting segment adjacent said clamping 3 member and movable within the gap to tension the plate on the cyilnder and form a part of the cylinder surface, one edge of the segment bearing on the clamping member opposite to the plate ends to lock the plate under tension on the cylinder.

11. A plate-clamp for holding a flexible plate having right-angled bent-over ends and wrapped about a printing cylinder having a gap comprising a spring-pressed clamping member to grip and hold the plate ends interposed between the member and one of the edges of the gap, a platesupporting segment pivoted within the gap adjacent said clamping member to form a part of the cylinder surface when forced into contact with the plate adjacent one of the plate ends, and means for raising said segment with one edge thereof bearing on the clamping member to lock the plate under tension on the cylinder, the surface of the segment in its raised position being coincident with the periphery of the cylinder.

12. In a printing cylinder having a gap and having a flexible plate wrapped about the cylinder with both bent-over ends arranged in mutual parallelism within the gap adjacent one of its edges, a single clamping member pivotally mounted within the gap, and means for yieldingly forcing said member to rock angularly with respect to the cylinder to grip both bent-over ends of the plate against said edge, the top surface of said clamping member forming a part of the supporting surface for the plate on the cylinder. 13. A plate-clamp for positioning a flexible plate wrapped about a printing cylinder having a gap comprising a single pivotally mounted clamping member, means for moving said member angularly within the gap to first lock both bent-over ends of the plate in surface-to-surface contact against one edge of the gap, a plate supporting segment adjacent the clamping member, and means for thereafter moving said segment outwardly within the gap substantially to the periphery of the cylinder to tension the plate on the cylinder, the top surfaces of the clamping member, said segment and the cylinder supporting substantially the entire under surface of the plate.

14. A plate-clamp for positioning a flexible plate wrapped about a printing cylinder having a gap comprising a single longitudinally disposed pivotally mounted clamping member, means for moving said member transversely within the gap to first lock both bent-over ends of the plate in surface-to-surface contact against one edge of the gap, a plate supporting segment adjacent the clamping member, and means for thereafter moving said segment outwardly within the gap substantially to the periphery of the cylinder to tension the plate on the cylinder, the top sur faces of the clamping member, said segment and the cylinder supporting substantially the entire under surface of the plate.

15. A plate-clamp for positioning a flexible plate wrapped about a printing cylinder having a gap comprising a single pivotally mounted clamping member, means. for moving said member angularly Within the gap to first lock both bent-over ends of the plate in surface-to-surface contact in mutual parallelism against one edge of the gap, a movable plate-supporting segment within the gap to tension the plate on the cylinder, and means for thereafter moving said segment outwardly and substantially to the periphery of the cylinder, the top surfaces of the clamping member and the segment forming a substantially continuous part of the cylinder surface.

16. A plate-clamp for positioning a flexible plate wrapped about a printing cylinder having a gap comprising a single pivotally mounted clamping member, means for moving said member angularly within the gap to first lock both bent-over ends of the plate in surface-to-surface contact in mutual parallelism against one edge of the gap, a movable plate-supporting segment within the gap to tension the plate on the cylinder, and means for thereafter moving said segment outwardly andsubstantially to the periphery of the cylinder, the top surfaces of the clamping member and the segment forming a substantially continuous part of the cylinder surface, and means for withdrawing the segment within the cylinder gap to loosen the plate on the cylinder without moving the clamping member from its locked position.

17. A printing cylinder having a gap at single pivotally mounted clamping member, means for moving said member transversely within the gap to first lock both bent-over ends of a flexible plate in surface-to-surface contact against one edge of said gap, a plate supporting segment, means for thereafter moving said segment outwardly within the gap substantially to the periphery of the cylinder for tensioning the plate, the top surfaces of the clamping member, said segment and the, cylinder supporting substantially the entire under surface of the plate. 1

18. A printing cylinder having a gap, a single pivotally mounted clamping member, means for moving said member angularly within the gap to first lock both bent-over ends of a flexible plate in surface-to-surface contact against one edge of said gap, a plate supporting segment, and means for thereafter moving said segment outwardly within the gap substantially to the periphery of the cylinder for tensioning the plate, the top surfaces of said clamping member and of said segment being adjacently coincident with the periphery of the cylinder.

19. A printing cylinder having a gap, a single pivotally mounted clamping member, means for moving said member transversely within the gap to first lock both bent-over ends of a flexible plate in surface-to-surface contact against one edge of said gap, a plate supporting segment, and means for thereafter moving said segment outwardly within the gap substantially to the periphery of the cylinder for tensioning the plate independently of the clamping member and without moving the latter, the top surfaces of the clamping member, said segment and the cylinder supporting substantially the entire under surface of the plate.

20. A printing cylinder having a gap, a single pivotally mounted clamping member angularly within the gap to first lock both bent-over ends of a flexible plate in surface-to-surface contact against one edge of said gap, a plate supporting segment, and means for thereafter moving said segment outwardly within the gap substantially to the periphery of the cylinder for tensioning the plate independently of the clamping member and without moving the latter, the top surfaces of said clamping member and of said segment being adjacently coincident with the periphery of the cylinder.

ANTHONY S. BUSK. 

